Power and energy, in plain terms
Think of a car. Speed in km per hour is how fast you are going right now. Distance in km is how far you went. Watts and kilowatts are like speed: how hard an appliance is working. Kilowatt hours are like distance: how much energy it used over a period.
1,000 watts make one kilowatt. Run a 1 kW appliance for an hour and it uses 1 kWh. Run a 2 kW heater for half an hour and it also uses 1 kWh. On the Ausgrid reference rate of 33.14c, every one of those kWh costs the same.
| Appliance | Power | Time to use 1 kWh |
|---|---|---|
| 10 W LED globe | 10 W | 100 hours |
| 100 W TV | 100 W | 10 hours |
| 1,000 W microwave | 1 kW | 1 hours |
| 2,000 W heater | 2 kW | 30 minutes |
Where you see kW and kWh
| Item | Unit | What it tells you |
|---|---|---|
| Your electricity bill | kWh | How much energy you used. See usage charges. |
| Appliance label | W or kW | How much power it draws while running. |
| Energy rating label | kWh a year | Tested yearly energy use. |
| Rooftop solar system | kW | The most power the panels can produce at once. |
| Home battery | kWh | How much energy it can store. |
| Demand tariff | kW | A charge based on your highest power use in a set window. See tariff types. |
| Air conditioner capacity | kW | Heating or cooling output, not the electricity it draws. |
Turning watts into dollars
Find the watts
On the appliance label or in the manual.
Divide by 1,000
2,400 W is 2.4 kW.
Multiply by the hours
2.4 kW for 3 hours is 7.2 kWh.
Multiply by your rate
7.2 kWh at 33.14c is about $2.
Skip the maths
Our appliance running cost calculator does this for 39 appliances on your state's rates.
Questions about kW and kWh
A kW measures power, how fast energy is being used right now. A kWh measures energy, how much was used over time. One kW used for one hour is one kWh.
It uses 2 kWh for every hour it runs at full power. In 30 minutes it uses 1 kWh.
Solar panels are rated by the most power they can produce at once, in kW. A battery is rated by how much energy it can store, in kWh.
It depends on household size and climate. The AER benchmarks put a two-person Sydney home at about 14 kWh a day averaged across the year, with more in winter and less in spring.
Yes. When people talk about units on a power bill, they mean kilowatt hours.
Sources
Every rate on this page comes from the regulator or the regulated retailer. Last checked October 2026. Prices include GST unless we say otherwise.